At the end of last winter my 4X4 SOTF stopped working. (98, 4.6l) I did a little investigating in the spring and then I left it because I'm a procrastionator. But I have some time now and I want to fix it before winter. I already checked the vacuum line for leaks and I narrowed it down to either the vaccum motor (actuator) or the relays on the fire wall. I tried to remove the actuator but it would not budge any tips? Also I believe I read in a post a while back that somebody had the same problem so the dismantled it in place any tips or links to that post would be appreciated. Also anybody that has been through this problem could you please post all part #'s and prices and where you purchased your parts. Sorry for the long post just trying to give all info.

Thanks
Mark M

 

Sounds like the same problem I have (see post below). Is yours' the switch on the dash, or the lever on tranny hump? Aren't they all SOTF? Mine is the tranny hump style. My vacuum motor is seized to the diff casting also. Removed the E clip, but can't budge the motor. My feeling is that it is related to the GEM, but who knows. When it did work, I could hear a click behind dash on passenger side, not now. That may have been the solenoids for vacuum, but it sounded like it was inside the truck, but maybe not. You might try reversing the lines for the vacuum motor, and see if it engages the front end, my feeling is that the 4X4 light wouldn't go on then, but the front end would lock. Let us know what you come up with

Cheers

Dan...AKA Schwerm

 

I just switched the vacuum leads on my motor, front end locked when I did this, it should show you if your vacuum motor is working. My feeling is that my problem is the GEM, could be yours too.

 

I also tried swaping the vacuum lines at the motor but it still didn't work so I decided to take apart the vacuum motor since I couldn't get it out. When I got it apart alot of rust particles fell out. I took a bunch of pictures but I'm not sure how to post them here. After cleaning everything up and re-assembling, it seemed to work but I wasn't hearing the loud clunk from the front end that I've heard in the past. I'm not sure my troubles are over. Tommorow I'll give it another look and test drive.